A043218 - OEIS

%I #10 Aug 23 2021 21:44:37

%S 30,103,130,203,230,300,330,403,430,503,530,603,630,703,730,803,830,

%T 903,930,1003,1030,1103,1130,1203,1230,1300,1330,1403,1430,1503,1530,

%U 1603,1630,1703,1730,1803,1830,1903,1930,2003,2030

%N Numbers k such that 0 and 3 occur juxtaposed in the base-10 representation of k but not of k-1.

%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n],{0,3}]>0 || SequenceCount[IntegerDigits[n],{3,0}]>0,1,0],{n,2100}],{0,1}][[All,2]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Feb 16 2020 *)

%K nonn,base

%O 1,1

%A _Clark Kimberling_